Beijing health authorities said on Thursday that 456 clinics operating without a license were closed down and 888 boxes of medicines and 735 sets of equipment were seized in their joint campaign with police and the administration for industry and commerce between January and May.

The clinics were fined more than 310,000 yuan ($50,500) and six clinic workers have been put in criminal detention.

The health authorities warned that nearly 70 percent of the clinics did not have qualified medical workers, and more than 50 percent didn't have a single worker with a medical education.

Nearly 60 percent of the clinics also lacked basic sterilizing equipment.